1. Field of the Invention
This invention relates to a process of producing uric acid and more particularly to a multi-faceted process for producing uric acid of varying degrees of purity. Specifically, this invention relates to a process for producing increasingly pure quantities of uric acid from fecal matter containing uric acid.
2. Description of the Prior Art
Uric acid occurs in nature chiefly in the urinary excrement of animals, such as in marine guano, other bird feces and reptile feces. These materials are the main commercial sources of uric acid which is widely utilized in medical and university laboratories for studying and testing various human and animal diseases. In addition, uric acid is used in the synthesis of numerous other materials.
One of the chief difficulties in obtaining and purifying uric acid from such fecal matter has been the removal of certain highly colored pigments in addition to other trace contaminants. While known processes for purifying uric acid are generally acceptable for some of the above-enumerated purposes, uric acid of varying degrees of purity have different types of uses, and it would be highly desirable to have a single process capable of producing uric acid of various predetermined degrees of purity. In addition, no one has marketed a uric acid product or disclosed a method for producing a uric acid product which is sufficiently pure or crystalline to be capable of serving as an ideal reference standard.
German Pat. No. 462,353 discloses a process for purifying uric acid from marine guano by treating the fecal matter with a solution of water-soluble sulfides followed by filtering the uric acid after precipitation with mineral acid. Polish Pat. No. 47,019 discloses a somewhat different process for purifying uric acid from fecal matter by dissolving the fecal matter in a dilute base and then adding a reducing compound such as sodium sulfate. Separation of the uric acid is then accomplished by precipitating the uric acid with mineral acid, followed by washing and drying the product. Both of the above processes result in a considerable loss of uric acid and produce a uric acid product of insufficient purity to be utilized as a reference standard. Furthermore, none of the above patents disclose a single process for producing different degrees of uric acid purity.
U.S. Pat. No. 2,302,204 discloses an additional process for purifying uric acid from animal fecal matter. This process, however, merely utilizes a series of steps wherein the uric acid is alternately dissolved in a dilute alkali solution and then precipitated through the use of either mineral acid or by cooling the dilute alkali solution. Prior to the final step, the uric acid is dissolved once again in a dilute alkali solution which is then decolorized utilizing carbon. This process, as in the above-mentioned processes, basically utilizes well known steps and achieves a uric acid product which is insufficiently pure to serve as a reference standard.